Application Experience of Bored Micropiles in the Conditions of Permafrost Soil

摘要

Results of pilot studies executed when strengthening foundation and tape bases of architecture monument - the building of National library of the Republic of Sakha (Yakutia) in Yakutsk are given. The article presents data on the kinetics of hardening of cement mortar with a complex additive NN+S-3 at low temperatures of permafrost soils. It is shown that the rate of hardening and strength of the solution greatly depend on the dosage of antifreeze component. A feature of the technology was also to determine the strength of cement mortar, with which possible pressure testing of the well. The strength of the mortar for re-injection should be not less than 10 MPa and not more than 20 MPa. The device technology of bored micropiles in permafrost soil is approved by the contractor - the Yakut branch "Svratka", Czech Republic. The received results indicate an opportunity and efficiency of micropiles application in conditions of permafrost soil.